- A. S. Brown and M. Losurdo and P. Capezzuto and G. Bruno and T. Brown and G. May, Fundamental reactions controlling anion exchange during mixed anion heterojunction formation: Chemistry and kinetics of P-for-As exchange reaction,
Journal Of Applied Physics, vol. 99 no. 9
(May, 2006) .
(last updated on 2009/09/08)
The fundamental chemical and kinetic surface processes governing the P-for-As exchange reaction during epitaxial layer synthesis are investigated. Exposure of a GaAs surface to phosphorus molecular beams (P-2) is carried out to create superlattice structures realized by surface reactions. The impact of the GaAs surface reconstruction, the P-soak time, and the surface temperature on the extent of intermixing and on the mechanism governing the anion exchange has been studied using x-ray diffraction, spectroscopic ellipsometry, x-ray photoelectron spectroscopy, and atomic force microscopy. It is found that As-rich GaAs surface reconstructions inhibit P-for-As exchange. The extent of the anion exchange increases with temperature. Furthermore, the P-for-As exchange is not controlled by P diffusion into the GaAs. We propose a chemical model that includes P chemisorption and indiffusion, and the competition between P-for-As anion exchange and the formation of AsP isoelectronic compounds. (C) 2006 American Institute of Physics.